1. Field
Aspects of the present disclosure relate generally to wireless communication systems, and more particularly to adjusting a carrier sense threshold to avoid hidden nodes during wireless broadcast.
2. Background
Wireless networks are widely deployed to provide various communication services such as voice, video, packet data, messaging, broadcast and other wireless communication services. These wireless networks may be multiple-access networks capable of supporting multiple users by sharing the available network resources. In a wireless local area network (WLAN), an access point supports communication for a number of wireless stations within the wireless network. In an ad-hoc mode, the wireless stations communicate in a peer-to peer (P2P) manner without an access point. Similarly, a peer-to-peer network allows the nodes to directly communicate with one another. In a peer-to-peer network, peer-to-peer nodes within range of one another discover and communicate directly without an access point.
During fast message dissemination in a large P2P wireless network, devices wake up periodically (e.g., once every minute) to broadcast a message until the information is exchanged among the devices. Any device that receives a message more recent than its current message, updates the current message and starts broadcasting the updated message based on the recent message. Each device may sense a shared channel before broadcasting the updated message. When a channel noise level sensed from the shared channel is above a carrier sense threshold (CST), the device knows the channel is busy and backs-off. Although devices are capable of sensing when the channel noise level is above the CST, many broadcast failures and collisions occur due to a hidden node problem.
A conventional solution to the hidden node problem includes a request to send (RTS) and clear to send (CTS) handshake for reserving the channel before transmitting actual data over the channel. Other solutions exist for different scenarios and system requirements, such as multiple channels, multiple radios, transmission power control, etc. These solutions, however, do not apply to broadcast messaging without RTS and CTS. Further, existing solutions address the hidden node problem for the purpose of increasing a continuous data throughput of each device.